Compound semiconductors

What type of band structure does gallium arsenide (GaAs) have?

  1. ADirect band gap
  2. BIndirect band gap
  3. CNo band gap
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Answer: A. Direct band gap

GaAs is a direct-band-gap semiconductor, so it emits light efficiently when electrons and holes recombine. That is why it is used in infrared LEDs and semiconductor lasers. Silicon has an indirect band gap, and because recombination involves lattice vibrations (phonons), its light-emission efficiency is extremely low.

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More Compound semiconductors questions

  1. Which is classified as a III-V compound semiconductor?
  2. What is the main reason GaAs has been used in RF amplifiers for mobile phones and similar applications?
  3. What are InP (indium phosphide)-based compound semiconductors mainly used for?
  4. Which material is mainly used in the light-emitting layer of blue LEDs?
  5. What is an advantage of alloy semiconductors such as AlGaAs?